Sturmey-Archer 5-speed disc hub- a unicorn?

[WoodlandHills]

Has anyone ever seen one of these or a found a place to buy one? SA identifies it as RX-RK5 on their site, but I have not been able to find anyone who sells it. Can anyone help? I tried all my usual suspects with no luck..... :? A 5-speed IGH with a DD 3rd gear would be just the thing for a dual-sport ebike.

 

[Chalo]

I find that I can break most internal gear hubs eventually, even without adding superhuman amounts of e-power. Sturmey Archer hubs are nothing special when it comes to robustness. I'd only trust them for power assist if I used them as mid drives, turning faster than normal to reduce torque at the hub.

Also, since S-A went to Taiwan, they make the 5-speed hub with a single chain shift. That causes intractable precision problems that cause the hub to shift poorly and inconsistently-- definitely not what you want for a power assist application.

For what you want: Rohloff first, NuVinci second, Shimano Nexus 3 third, Shimano Alfine fourth. The Nexus 3 is the cheapest option by far, even in the more expensive 135mm disc braked version.

 

[Deafcat]

to be fair, the "new" Sturmey Archer 5 speed hub is redesigned, and rated for "heavy duty" unlike anything else in their product line. It's also not a high cost, so it makes sense to put it to good use

Chalo ya no like Alfines? I believe the 7s or 8s (forget which specifically) are pretty damn tough. the 11 I've heard, not so much. I ran the 8 on my Dahon and it was just fantastic! purely human-powered contraption though.

I've been reading there's some considerable efficiency loss with the newer Nuvinci's, I love the concept of running CVT but definitely not going to adopt at a loss of efficiency just yet... though it seems their old units are tighter in this regard?


edit: unique option with SA hubs: you can get em with a drum brake

 

[WoodlandHills]

I am happy with the way my Nexus 3 is working, I just would like a 5-speed instead of the ol'three-on-a-tree...... I figure that to make room for a drum brake in the hub, they had to make the internals smaller and thus weaker, plus I like discs. Efficiency is not much of an issue: the BBSHD makes enough power to negate any driveline losses at this point. I am held back by only having three gears, not by only having 1.5hp.

 

[Thud]

Your best bet is yor friendly neighborhood bicycle shop....99% of the SA catolog is tough to access IME.

 

[Chalo]

to be fair, the "new" Sturmey Archer 5 speed hub is redesigned, and rated for "heavy duty" unlike anything else in their product line. It's also not a high cost, so it makes sense to put it to good use

Chalo ya no like Alfines? I believe the 7s or 8s (forget which specifically) are pretty damn tough. the 11 I've heard, not so much.

The gearbox of the S-A might be great; I don't know. What I do know is that shifting is a problem.

The old (English made) 5-speed had two controls-- a chain on the right for high/middle/low, and a bell crank on the left for wide range/narrow range. The shifter made everything happen in the right order. The new Taiwanese 5-speed crams all five shifter positions into the right side chain... which is precise enough for three positions, but not reliable for five. The result is gear skipping and subsequent damage to the internal shift dogs.

Alfine is great, no question. Nexus 8 too. But given the space constraints, it's impossible to fit 8 ratios into the same width as 3 and still have the same durability at a proportional price. You'll notice I didn't even mention Sturmey 8 or SRAM 9 or Sachs 7 speed hubs, because in my opinion they're not suitable for leg power plus motor power applications.

 

[fellow]

There is a sram i-3 Disc version here: https://www.sram.com/sram/urban/products/i-3-disc-brake
3 speed versions should have the best efficiency of them all, almost derailleur like. On the other side, i do not recommend it with central motor at all... but that's another story.

 

[Chalo]

In my observation, the SRAM i-Motion 3 is the most problematic of all the 3-speed hubs. It's a good-looking piece of equipment, but it's not dependable.

When it came out, SRAM made a big fuss about it having been designed entirely by computer, but it seems they would have done well to include some good old trial and error in their process too.

 

[WoodlandHills]

I got this automated response from Sturmey-Archer. It seems that the Rotary C50 5-speed they mention as being available in 2015 is the one I am looking for. This is the one with direct drive 3rd gear and 135mm width and, of course, the disc brake. Obviously things are running late, hopefully I can get one in 2016. :lol:


Hello and Thank you for contacting Sunrace Sturmey Archer.

This is the e-mail address for North America. If you are outside of North America please e-mail info@sunrace.nl for Europe and info@sunrace.com for everywhere else.

Please do not send multiple e-mails. Your e-mails will be returned unless your question was answered with this auto response.

Our new wide ratio CSMX 10 and 11 speed cassettes are in production and are now available. Please have your local bikeshop contact one of our distributors for further information.

Our new Rotary C50 5 Speed hubs will be available later this year (2015). Currently all production is going to our OEM partners.

If you are interested in the S3X fixed gear 3 speed hub, S2C 2 Speed Kickback Coaster, or S2 2 Speed Kickback freewheel hub, they are now in production and readily available through any of your local bike shops or many online retailers.

If you are interested in obtaining Sturmey Archer hubs and or spare parts for current hubs please check the following:

http://sunrace-sturmeyarcher.blogspot.com/2009/05/sturmey-archer-wholesale-and-retail.html

If you are looking for vintage parts we unfortunately do not manufacture parts for hubs pre 2000. Although all of the exterior fittings from our current hubs will work on most older hubs. Parts such as shifters, axle nuts, indicator chains, etc, will fit most vintage 3 and 5 speed hubs.

E-mails will not be returned if you are looking for basic information that can be found on both of our websites: http://www.sunrace.com & http://www.sturmey-archer.com

Thank you for contacting Sunrace Sturmey Archer.


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[WoodlandHills]

I followed up with BTI, the distributor that SA referred me to. and they placed their order for these hubs back on 10/24/15. It usually takes 3 months for delivery, so they should be in stock in a couple of weeks for shipment to your LBS. I am going to check back in mid-Feb and see if I can get one to try out.

Here is a link to the hub at the SA distributor: BTW silver only

http://www.bti-usa.com/public/item/UR6514?track=true